MONTPELIER — Two advocacy groups are looking to help defend the state against an industry group lawsuit against Vermont’s GMO labeling law.

The Vermont Public Interest Research Group and the Center for Food Safety say they have filed papers to formally move for party status in the lawsuit against Act 120, which was signed into law in May by Gov. Peter Shumlin. It requires the labeling of food with genetically engineered ingredients.

The two groups want to intervene on behalf of the state to assist in defending the law. Both groups are being represented jointly by lawyers from CFS and the Vermont Law School’s Environmental and Natural Resources Law Clinic.

The Grocery Manufacturers Association, the largest group of food manufacturers in the country, as well as the Snack Food Association, International Dairy Foods Association and National Association of Manufacturers, filed suit against the law about a month after it was signed. The state’s response to the suit is due Aug. 8.

The food industry has poured tens of millions of dollars into anti-labeling campaigns in other states, according to the groups.

“Corporations don’t get a veto in the state of Vermont,” said George Kimbrell, a senior attorney for CFS who will serve as the lead attorney for VPIRG and CFS. “We will vigorously defend this legally sound and important law, which is critical to our members and our mission.”

Paul Burns, executive director of VPIRG, said his group is prepared to contribute resources to help the state defend the law.

“Vermonters take their food seriously, and this law gives them the information they need to make informed purchasing choices,” Burns said. “VPIRG will do whatever we can to defend the GMO labeling law from corporate bullies who would rather keep consumers in the dark about what’s in their food.”

Falko Schilling, VPIRG’s leading advocate for GMO labeling, said it is unclear exactly how much the legal effort will cost.

“I can’t put a figure on that at this point,” he said. “We’re basically putting forward whatever resources we can. We’re going to have to raise some resources, I believe, to mount a strong defense.”

Attorney General Bill Sorrell has said Assistant Attorney General Megan J. Shafritz, chief of the attorney general’s civil division, will serve as the lead attorney for the state. The litigation team defending the law will include in-house attorneys Jon Alexander, Kyle Landis-Marinello and Naomi Sheffield. It will also employ attorneys from the Washington, D.C., firm Robbins, Russell, Englert, Orseck, Untereiner & Sauber LLP, which struck a $1.465 million contract with Sorrell’s office.

Sorrell told lawmakers the legal effort could cost the state as much as $8 million if it loses the case.

Vermont’s law, set to take effect in July 2016, is seen as a key battle in whether or not food companies will be required to label products with genetically modified ingredients. Two other states, Connecticut and Maine, have passed food labeling laws that are contingent on other states passing similar legislation. And Oregon has a ballot initiative on the November ballot.

Mary-Kay Swanson, executive assistant to Sorrell, who was out of state Tuesday, said the state is not opposing intervention by VPIRG and CFS, but the court will decide if they meet the legal standard for party status. She said the state is planning to mount a strong defense regardless.

“There’s no question that the state will vigorously defend this law and that we have the resources and expertise at our disposal,” she said. “In no way will this case be hindered by us having to pinch pennies.”

Schilling said both VPIRG and CFS can help boost the state’s defense of the law if they are granted party status.

“This is an issue that we have been involved with ... and we have a long history of working on and we feel we can bring a lot of things to the table,” Schilling said. “That’s why we’re pushing to intervene. We believe the law is constitutional and believe it will be upheld.”